Single-walled carbon nanotubes (SWNTs) are being widely investigated as agents for the near infrared (NIR) - mediated thermal ablation of tumor cells because they efficiently convert absorbed NIR light into heat. Despite the therapeutic potential of SWNTs, there have been no published studies that correlate how many SWNTs need be associated with a cell to achieve a measured outcome of killing, or what is the most efficient subcellular distribution of SWNTs for killing cells. This is important information for the rational design and testing of strategies to eventually deliver an effective payload to tumor cells in vivo. The main reason for this knowledge gap has been the lack of methods for quantitatively assessing the amounts and subcellular location of SWNTs in cells. We have recently developed methods to extract and measure small amounts of cell-associated SWNTs and to directly image their distribution in cells by 3-dimensional confocal Raman microscopy. The overall objective of this proposal is to correlate NIR-mediated cell death with the quantity and location of cell-associated SWNTs in vitro and then carry this information to initial studies of a tumor model in mice. Specific aim 1, to determine the efficacy of NIR-mediated ablation of target cells as a function of the amount of cell-associated SWNTs. The objective of specific aim 1 is to correlate the actual dose of cell-associated SWNTs with the extent of cell death, distinct from the usual LD50 curves that relate killing to the amount of drug in the medium or injected into the blood of an animal. Specific aim 2, to determine the efficacy of NIR-mediated ablation of target cells as a function of the subcellular location of SWNTs. The objective of specific aim 2 is to generate data that correlates the effectiveness of NIR-mediated ablation with SWNT subcellular location, on the plasma membrane or within lysosomal vesicles. Specific aim 3, pilot studies on ablation of human BT-474 tumors growing on NOD/SCID mice using anti-Her-2-MAb-SWNT constructs. The objective of this study is to learn whether the amount of SWNTs targeted to wither the plasma membrane or lysosomes impacts the extent of tumor cell ablation in an in vivo model of human tumors growing on mice. Together, the work in this proposal will provide insight into the influence of dose and subcellular location on the effectiveness of SWNTs in NIR-mediated cell ablation with in vitro and in vivo tumor models. PUBLIC HEALTH RELEVANCE: Single-walled carbon nanotubes are a promising new material for cancer therapy because they have the ability to heat up and kill tumor cells when exposed to certain types of light. This proposal details quantitative studies to assess the effectiveness of single-walled carbon nanotubes as agents for the thermal destruction of tumor cells using in vitro and in vivo tumor models.